EP 1689075 A1 20060809 - MULTI-STAGE AMPLIFIER TO REDUCE POP NOISE
Title (en)
MULTI-STAGE AMPLIFIER TO REDUCE POP NOISE
Title (de)
MEHRSTUFIGER VERSTÄRKER ZUR ABSCHWÄCHUNG DER STÖRIMPULSE
Title (fr)
AMPLIFICATEUR À PLUSIEURS ÉTAGES POUR RÉDUIRE LE BRUIT DE TYPE <POP>
Publication
Application
Priority
EP 05290244 A 20050203
Abstract (en)
An amplifier (50) for voice or audio signals, and particularly for headset applications, uses a low g m amplifier (54) for initially charging an output node (OUT) at the beginning of a power-on phase. After charging the output node, a main amplifier (56) is enabled to amplify the voice or audio signal. At power-down, a sample-and-hold circuit (58) drives an output transistor to discharge an AC coupling capacitor (20). Thus, spikes at the output node are eliminated and an external filtering capacitor is not needed.
IPC 8 full level
CPC (source: EP US)
H03F 1/305 (2013.01 - EP US); H03F 3/3022 (2013.01 - EP US); H03F 3/72 (2013.01 - EP US); H03F 2203/7227 (2013.01 - EP US); H03F 2203/7231 (2013.01 - EP US)
Citation (applicant)
- EP 1229639 A2 20020807 - SONY UK LTD [GB]
- US 6438364 B1 20020820 - WAITE HELEN MARGARET [US]
- US 5648742 A 19970715 - GHAFFARIPOUR PARVIZ [US], et al
Citation (search report)
- [Y] EP 1229639 A2 20020807 - SONY UK LTD [GB]
- [Y] US 6438364 B1 20020820 - WAITE HELEN MARGARET [US]
- [A] US 6064327 A 20000516 - RYOHO FUMIHIRO [JP], et al
- [A] US 6204654 B1 20010320 - MIRANDA EVALDO M [US], et al
- [A] US 5648742 A 19970715 - GHAFFARIPOUR PARVIZ [US], et al
Designated contracting state (EPC)
DE FR GB
DOCDB simple family (publication)
EP 1689075 A1 20060809; EP 1689075 B1 20180711; US 2006182265 A1 20060817; US 8965010 B2 20150224
DOCDB simple family (application)
EP 05290244 A 20050203; US 17578405 A 20050705